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參數(shù)資料
| 型號： | TPS65105RGE |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | TRIPLE OUTPUT LCD SUPPLY WITH LINEAR REGULATOR AND VCOM BUFFER |
| 中文描述： | 三路輸出液晶供應線性穩(wěn)壓器和VCOM緩沖器 |
| 文件頁數(shù)： | 19/25頁 |
| 文件大?。?/td> | 816K |
| 代理商： | TPS65105RGE |
www.ti.com
Vout
1.214
1
R5
R6
R5
R6
Vout
VFB
1
R6
Vout
1.214
1
TPS65100
TPS65105
SLVS496B–SEPTEMBER 2003–REVISED MARCH 2004
Voltage tripler:
Vo3
max
= 3
×
Vo1 - (3
×
V
D
+ 2
×
Io
×
(3
×
r
DS(on)Q5
+ r
DS(on)Q3
+ r
DS(on)Q4
+ X
C1
+ X
C2
))
The output voltage is set by the external resistor divider and is calculated as:
VCOM Buffer
The VCOM buffer is typically used to drive the backplane of a TFT panel. The VCOM output voltage is typically
set to half of the main output voltage Vo1 plus a small shift to implement the specific compensation voltage. The
TFT video signal gets coupled through the TFT storage capacitor plus the LCD cell capacitance to the output of
the VCOM buffer. Because of these, short current pulses in the positive and negative direction appear at the
output of the VCOM buffer. To minimize the output voltage ripple caused by the current pulses, a
transconductance amplifier having a current source output and an output capacitor is used. The output capacitor
supports the high frequency part of the current pulses drawn from the LCD panel. The VCOM buffer only needs
to handle the low frequency portion of the current pulses. A 1-μF ceramic output capacitor is sufficient for most of
the applications. When using other output capacitor values it is important to keep in mind that the output
capacitor is part of the VCOM buffer loop stabilization.
The VCOM buffer has an integrated soft start to avoid voltage drops on Vo1 during start-up. The soft start is
implemented as such that the VCOMIN is held low until the VCOM buffer is fully biased and the common mode
range is reached. Then the positive input is released and the VCOM buffer output slowly comes up. Usually a
1-nF capacitor on VCOMIN to GND is used to filter high frequency noise coupled in from Vo1. The size of this
capacitor together with the upper feedback resistor value determines the start-up time. The larger the capacitor
from VCOMIN to GND, the slower the soft start.
Linear Regulator Controller
The TPS65100/05 includes a linear regulator controller to generate a 3.3-V rail when the system is powered from
a 5-V supply. Because an external npn transistor is required, the input voltage of the TPS65100/05 applied to
VIN needs to be higher than the output voltage of the regulator. To provide a minimum base drive current of 13.5
mA, a minimum internal voltage drop of 500 mV from V
in
to V
base
is required. This can be translated into a
minimum input voltage on VIN for a certain output voltage as the following calculation shows:
VIN
min
= Vo4 + V
BE
+ 0.5 V
The base drive current together with the h
FE
of the external transistor determines the possible output current.
Using a standard npn transistor like the BCP68 allows an output current of 1 A and using the BCP54 allows a
load current of 337 mA for an input voltage of 5 V. Other transistors can be used as well depending on the
required output current, power dissipation, and PCB space. The device is stable with a 4.7-μF ceramic output
capacitor. Larger output capacitor values can be used to improve the load transient response when higher load
currents are required.
Layout Considerations
For all switching power supplies, the layout is an important step in the design, especially at high-peak currents
and switching frequencies. If the layout is not carefully designed, the regulator might show stability and EMI
problems. Therefore, the traces carrying high-switching currents should be routed first using wide and short
traces. The input filter capacitor should be placed as close as possible to the input pin VIN of the IC. See the
evaluation module (EVM) for a layout example.
19
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| TPS65105RGER | 功能描述:LCD 驅動器 LCD Supply with Vcom Buffer RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| TPS65105RGERG4 | 功能描述:LCD 驅動器 LCD Supply with Vcom Buffer RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| TPS65110RGE | 功能描述:電荷泵 Triple Chargepump for LTPS LCD RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| TPS65110RGEG3 | 功能描述:電荷泵 Triple Chargepump for LTPS LCD RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
| TPS65110RGER | 功能描述:電荷泵 Triple Chargepump for LTPS LCD RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube |
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